It's not clear that having your own datacenter is more secure than using AWS/GCP/Azure services. In both cases there are good monitoring solutions, however I'd say that cloud-based solutions have easier immediate access to most things because they just integrate with the provider's API whereas on prem you're installing agents and whatnot.
Also having granular IAM for services and data is very helpful for security. You have a single source of truth for all your devs, and extremely granular permissions that can be changed in a central location. Contrast to building out all of that auditing and automation on your own. Granted, IAM permissions give us tons of headaches on the regular, but on balance I still think it's better when done well.
If you're concerned about AWS/GCP/Azure looking at your private business's data, I think 1.) that's explicitly not allowed in the contracts you sign 2.) many services are HIPAA compliant, hence again by law they can't 3.) They'd for sure suffer massively both legally and through loss of business if they ever did that.
Also having granular IAM for services and data is very helpful for security. You have a single source of truth for all your devs, and extremely granular permissions that can be changed in a central location. Contrast to building out all of that auditing and automation on your own. Granted, IAM permissions give us tons of headaches on the regular, but on balance I still think it's better when done well.
If you're concerned about AWS/GCP/Azure looking at your private business's data, I think 1.) that's explicitly not allowed in the contracts you sign 2.) many services are HIPAA compliant, hence again by law they can't 3.) They'd for sure suffer massively both legally and through loss of business if they ever did that.